Metal boat construction



May 19, 1931.

n; LIAMIN METAL BOAT CONSTRUCTION Filed July 17, 1928- l st-rented Mayid,

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racer eastern-season Application filled July 17,, serial l lo, 2%,4753.

This invention relates to the art of ship building and is moreparticularly a method.

( tion without the ordinarily employed cast- I secured to the keel ingand forging or hot bending o erations.

It is a particular object of this invention to develop a process wherebythe members of a boat or ship may be placed in position to conform tothe contour of a cubic parabola which has been found to be one of themost efficient forms of stream line construction. It will be understoodhowever that boats may be constructed by this process having any desiredshape of stream line such construction being; dependent entirely uponthe design of the vessel.

It is a further object of this invention to develop a process in whichthe fabrication of the boat is done entirely by welding, there being norolling or stamping oi the shell plates. These members are cut insections and are applied directly by pressure against cell'sin the framework which are formed by a system of transverse and longitudinal ribmembers, such members being secured to one another and the transversemembers being by means of welding. The longitudinal rib members are coldbent about the transverse rib members and are preferably received bysuitably formed recesses in the last mentioned members.

It will be understood that the process has a further object of greatlydecreasing the cost of boat construction since the forging or rolling orstamping operations are eliminated, and the placement of rivet holes andthe riveting of the respective parts which is a large factor in theexpense of boat construction, are also veliminated.

Other objects and advanta es in this method of boat construction w ll--be better onstrating the manner understood from the followindescription ofan illustrative embodiment o a vessel constructed by thismethod as shown in the accompanying drawings, in which Fig, 1illustrates the bed as may be constructed by the herein describedprocess.

Fig; 2 is a plan View illustrating the frame work of a boatrsuch as maybe constructed by the Process herein described.

F 1g. 3 is a sectional elevation taken sub- 7 stantially in a 3- in Fig.2.

Fig. 4 is an enlarged perspective view plane represented by the lineshowing a portion of the frame work of a 69 boat such as is illustratedin Fig. l and dQllQ-r of arranging and placing the respective parts orsections Fig. 5 is an enlarged sectional view which 1 may be consideredas having been'talren sub stantially in va plane by the line 5-5 in Fl adis an enlarged sectional view which may be considered as having beentaken in a plane indicated by the line 6-43 in Fig. 4.

Fig. 7 is a plan view illustrating'a preferred manner of forming thetransverse rib members, i

More particularly describing the invention,

as herein illustrated reference numeral 11 indicates a metal boat of thetype herein described which has a lreel l2 and side plating 13. It willbe understoodwhile this invention s described in connection with a smallcraft that it is not confined to any particularsize so or type of vesseland although in the vessel herein described the keel 12 is illustratedas supporting directly the transverse ribs indicated by referencenumeral 14, these ribs may; in a larger type of vessel be secured to asthe keelsons.

' The ribs 14 may be formed in any desired manner and it will beunderstood that their curvature and strength are determined by thedesign of the vessel. I have found in the w) y of a boat suchde'velopment of this method that most satisfactory results areeconomically obtained by using substantially flat metal bars which maybe bent upon a bendin floor to conform to pattern or design which islaid out by the formed, they are er of the vessel, is marked out uponthe at metalsheet 14, such marking being indicated b reference numeral15, and the transverse llbS 14 are cut therefrom by means of anacetylene torch or any other suitable cutting mechanism commonly knownto those familiar with the art." I

After the transverse members have been provided with a series of notchesindicated y reference numeral 16, the 'tion of such notches being alsocalculat by the designer of thevessel and being arranged in alignmentthroughout the length of the transverse ribs. i

The transverse ribs are then placed in po-' sition upon the keel asindicated in the perspective view shown'in Fi 4 and are secured to thekeel which may' be in a form of united channel irons or an I beam, bymeans of welding such welding being indicated by reference numeral 18 onFi 4.

After the transverse r bs have been placed in position, the longitudinalribs 19 are at-v tac thereto by taking substantially straight and flatmetal bars, welding one end of such bars toone of the end transversemembers such as is indicated at 20in Fig. 2, and by means of a Windlassor by any other suitable power applying means, these bars,

formin the longitudinal members are bent throu out the respectivepositions illustrat-' ed in otted lines of'Fig. 2,.to be received by thereocesses 16in the transverse ribs and to conform thereby to thedesigned outline or profile of the vessel.

It will be understood that in bending these longitudinal ribs, it ispreferable to weld the bar pro 'vely to each transverse member as t elongitudinal bar 'is'brought into gement with the mentioned recess.

t will be understood by those familiar with the art, that metal such assteel, which is cold bent, during such a bending opera- 'tion asubstantially cubic parabola, the dimensions or outlines of which aredependent .u n the magnitude of the bending moment,

cross sectional area of the barand its bending or elastic strength. Itwill therefore be apparent to those familiar with the action of metalunder such. a strain, that themetal which is bent in this manner tendsto develop surface correspondin a cubic parabola which represents one othe closest approaches to a -s0-ca'lled idealv stream' line curvature.

I eliminates the 11: mm of artificial or hot bendin "which is costlyfromthe' standpoint of la r and requires skill much greater thandemanded in the It is a comparatively simple matter to out- I line fromthese sections or to calculate in the design ofthe vessel the pattern orform necessary to obtain .a uniform covering of such a section from asubstantially flat metal plate and from these patterns the mentionedplates are laid off and cut from sheets of metal plating. The platesections 21, 21', so out,

are attached to the rib members by means of welding. In such anattachment one edge of the plate is welded to one of the. rib membersand the plate is then bent to 'conform'to the curvature of the outlineof the frame work by means of a plurality of C clamps, such as are indicated at 22 in Fig. 4.

The plate 21 is illustrated as having been placed in position and theplate 21 being eld in'place preparatory to the welding operation, itclamps which press the plate to the longitudinal and transverse; ribmembers exercise a double bending moment around the horizontal andvertlcal axes of the plate and owing to the elasticity of the metal,-the platerec'eives a double deflection.

The horizontal deflection is guided by the run of the longitudinal ribsand the vertical. deflection depends upon the thickness of the plateand-the magnitude of the curvature of these ribs at the point at whichthe plate is bein applied.

The rst factor may be considered as being a constant and the second oneas a variable w1ll be understood that the C stream line curvature. Themagnitude of the vertical deflection should not trespass thecontractional limit of the elasticity of the metal, surpassing which themetal would tend to corrugate or buckle. This limit as was mentionedabove is guided by the curvature of the vessel at the point at which theplate is to be applied, audit will be understood that the'exact area towhich each plate must conform in order to define a certaincu'rvawere;readily calculated and'by means of such calculations, members ma whichwill) a maximum area.

be arranged to form spaces 't the use of plates having :1

Such calculations are howevera' matter of the ship design which will theintersecting rib asoaeea corpugation (l) (D /2+ i 0=d (2 swede-sesameb=vertical width of plate I Z=horizontal length of plate D=maximumhorizontal deflection 0 plate d=maximuni vertical deflection of platet=thickness of plate G=constant dependent upon the elasticity of theplate material The length L may represent either one or a plurality ofspans between the transverse frames. The thickness of the plates 25 isdetermined in accordance with Lloyds Regulations. The maximumlongitudinal defiection D for the assumed length of plate L isdetermined from the boat oil'sets what ever the design may be. Theconstant ,C is calculated from the following equation:

0 .75 "EX it in which:

Y=yield point of the metal used E=coeiiicient ofielasticity of the metalmaximum allowable stress ultimate strength After the values of L, D andC have been determined, the value of (i may be calculated bysubstitution in Equation 1. From the value of 03 thus computed the valueof b is found from table of the boat offset, whatever the design may be.I

Formula 2 is used to check the validity of the above obtained valueswith reference to the thickness of the particular plate section beingused. The minimum allowable thickness 25 may be obtained from anystandard hand book such as Lloyds or the United States, Shipping BureauRegulations. In

case the values of d and 25 found from Equation 1 do not satisfyEquation 2, the assumed length L must be taken shorter by one or morespans between the transverse frames so that the new values of d and bwill satisfy Equation 2.

In-the usual practice of my invention I employ a few mainlongitudinalsrunning the entire length of the ship. If the value ,b found-from thevalue of d calculated from Equation 1 cell, or-area betweenlongitudinalsand ribs at one section, is found to,be less than theabove,, for any particular l distance between the main longitudinals atthis point, one or more supplementary longitudinals must be positionedbetween the main longitudinals to bring the area of the cell down to apoint at which the desired curvature can be obtained without buckling orcorrugating the plates.

In welding the plates to the mentioned rib members, it will beunderstood that the plates are provided with a dual Weld such as isindicated in Figs, 5 and 6, in which the plates indicated by referencenumerals 21 and 21,

are illustrated as being welded to the transverse ribs 13 at the pointsindicated by reference numeral 23 and the edge of each plate is attachedto an adjoining plate and to the transverse rib by a second weldindicated by reference numeral 24. In a like manner the plates 21 and21" are attached to the longitudinal ribs 19 by the welding indicated at25 and the edges of these adjoining plates are attached to each otherand to the longitudinal ribs by means of a center weld 24.

It will be understood that while I have herein described this process asapplied to one particular form of small craft, the di-.

mensions and arrangement of .the members described one application ofthis method, the same is not limited to the specific illustration, butincludes Within its scope such adapmay of course be varied dependingupon the design and size of the vessel, and while I have transverse ribsby cutting such ribs from substantially flat plates; providing saidtransverse ribs with aligned recesses; welding saidribs in spacedrelation with eachother to a keel; placing longitudinal ribs upon saidtransverse ribs by cold bending substantiallystraight metal bars intosaid aligned recesses and welding thereto to form a frame work; andplating said frame work by cold pressing fiat metal plate sections intoengagement with said ribs and welding said plate sections 7 to saidribs, said transverse ribs and said longitudinal ribs being sopositioned that the plates may be cold bent into engagement therewithwithout buckling.

2. A method of constructing metal boats which includes: the formation ofcurved transverse ribs by cutting such ribs from substantially flatplates; providing said transverse ribs with aligned recesses; weldingsaid ribs inspaced relation with each other to a heel; placinlongitudinal ribs upon said transverse ri s by cold bendingsubstantially straight metal bars into said aligned recesses and weldingthereto to form a frame work; and plating said frame work by coldpressingfiat metal plate sections into engagement with said ribs andwelding said plate sections plates may be co d-bent into engagementtherewith without buckling.

3. A method of constructing metal boats which includes: providintransverse ribs with aligned recesses; wel ing said ribs to a a m keelin spaced relation with each other;

mountin longitudinal ribs upon said transverse ri s b co'ld bendingsubstantially straight meta bars into said aligned recesses and weldingthereto to form a frame work; 15 and platin said frame work by pressingsubstantially at metal plate sect ons into engagement with said ribs andwelding the, edges of said plate sections to said ribs, said transverseribs and said longitudinal ribs 90 being so positioned that the platesmay be cold bent into engagement therewith without buckling. I 4. A met0d of constructing metal boatswhich includes: providin transverse ribsas with aligned recesses; wel ing said ribs to a keel in' spacedrelation with each other; mountin longitudinal ribs upon said transverseri s' by cold bendin substantially straight metal bars into sai alignedrecess I so and welding thereto to form a frame work;

and platin said frame .work by pressing substantia y flat metal latesections into engagement with said ribs and welding the edges of-saidplate sections to said ribs, and 85 to theedges of adjacent platesections, said transverse ribs and said longitudinal ribs being sopositioned that the plates may be cold bent into engagement therewithwith out buckling. v o 5. A met 0d of constructing metal boats I whichcom rises: building a framework consisting o a plurality of transverseand longitudinal ribs, arranged to'form a plurality of cell spaces; coldbending flat metal p ate sections into positions such that the ed es ofsaid plate-sections enga e the ribs do 'ng said cells;and attachingteedges of said plates to said ribs, the'area of said plates being suchthat the vertical deflection of said "50 plates resulti'rzfi from saidcold-bending doesnot trespass e contractional limit of the elasticity ofthe metal.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 9th 55 day of July, 1928.

. I DIMITRI LIAMIN.

